Variable speed gear and means for controlling the same



1,619,701 March I 1927' A. E. L. CHORLTON VARIABLE SPEED GEAR AND MEANSFOR CONTROLLING THE SAME Filed July 7, 1924 5 Sheets- Sheet 1 FIG/.-

llW/E/VTOH 1,619,701 March 1 1927' A. E. L. CHORLTON VARIABLE SPEED GEARAND MEANS FOR CONTROLLING THE SAME Filed July 7. 1924 5 Sheets-Sheet 2 a5. KM,

m, c@,; -/%MM March 1 1927. l,619,701

A. E. L. CHORLTON VARIABLE SPEED GEAR AND MEANS FOR CONTROLLING THE SAMEFiled July 7, 1924 5 Sheets-Sheet 5 1 192 March 7 I A. E. L. CHORLTONVARIABLE SPEED GEAR AND MEANS FOR CONTROLLING THE SAME 5 Sheets-Sheet 4IL-i 1 192 March 7 A. E. L. CHORLTON VARIABLE SPEED GEAR AND MEANS FORCONTROLLING THE SAME Filed July '7, 1924 5 Sheets-Sheet 5 Patented Mar.1, 1927.

NITED-sures PATENT OFFICE.

VARIABLE SPEED GEAR AND MEANS FOR CONTROLLING THE SAME.

Application fil ed July 7,

This invention relates to variable speed gears more especially those ofthe spur wheel epicyclic type and to the means whereby such gears may becontrolled.

Where it is necessary to use a variable speed gear in a powertransmission system comprising a prime mover of considerable horsepower, as for instance in the case of an internal combustion enginelocomotive, the

forces developed are such that it is not practicable to employconstructions of speed gear and methods of controlling the same such aswould be possible where less horse power is being transmitted. It hasbeen found necessary to employ for this purpose a gear of the spur wheelepicyclic type, but whereas it has been customary to control the speedvariations in such gears by band brakes, cone clutches and such likedevices in cases 0 where relatively a small horse power has had to betransmitted through the gear, the employment of these devices isimpracticable with a prime mover developing. for example, 1000 or 1500horse power which has to be transmitted to track wheels through thevariable gear. It becomes necessary then to provide some means by which.while the desired range of speeds may be obtained, the speed changes maybe carried out and controlled in a manner which will give in effect aconsiderable range in transmission ratios without risk of such shocks orstrains as would be liable to cause damage to the transmissionmechanism.

According to this invention this end is attained by employing connectingdevices of the plate type which are operative on the elements of thegear train so as to brin about all the speed variations while, further,these connecting devices are controlled in such a manner as to effecttheir engagement and release and permit a variable degree of slipbetween the clutch members. This control is conveniently effected byfluid.

means. Thus while the gear train may be constructed to provide certaindefinite transmission ratios, it is possible to vary these while thedrive is being transmitted by slipping of the several connecting devicesto a variable extent so that any change from one fixed gear ratio toanother may be carried 1924. Serial No. 724,719.

out gradually without shock to the mechanism.

A further feature in the invention is the provlslon of a gear structureparticularly suited for use in this way the gear structure comprismg oneor more epicy clic gear trains. Such gear structure is also combinedwith plate connecting devices specially suited for use in the mannerindicated.

The invention also relates to the means by which these connectingdevices may be operated and controlle The accompanying drawingsillustrate by way of example structures of variable speed gear,connecting devices and means for controllmg the same such as may beemployed in putting. the invention these drawings all of grammaticnature igure 1 is a longitudinal sectional elevation illustrating by wayof example one form of single epicyclic gear train as constructed,arranged and adapted to be controlled to enable speed variations to beobtained in accordance with this invention.

igure 2 is a similar view of one form of variable speed gear comprisingtwo epicyclic gear trains with connecting devices for controlling them.Figure 3 is again a similar view illustratmg an alternative arrangementof a single :pmyclic gear train embodying the inven- Ion.

Figure'4 shows in longitudinal section a construction of control valveand the mechanism for supplying liquid under pressure to the severalconnecting devices in the conwhich are of a diag struction of gearillustrated in Figure 2.

Figure 5 is a transverse section on the line 5-5 through the controlvalve shown in Figure 4 together with the pipe connections for conveyingliquid under pressure to the connecting devices in the gear shown inFigure-2 and for relieving the pressure from these connecting devices.

Figure 6 is a transverse section on the line 6-6 through the controlvalve shown in Figure 4.

Figure 7 is a similar section taken on the Figure 4.

- line 7-7 through the control valve shown in into practice. In

Figure 8 is a projection on the flat of the external surface of thevalve shown in Figure 4. illustrating the arrangement of the passagesand ports in this valve. 7

Figure 9 is a similar projection on the flat of the interior surface of.the valve body shown in Figure 4 illustrating thedisposition of theports and passages in this body.

Like letters indicate like parts throughout the drawings.

Referring first to the single gear train illustrated in Figure 1, thedriving shaft A is disposed coaxially with the driven shaft B powerbeing applied from some suitable prime mover to the shaft-A while theshaft B is coupled to or provided with some convenient means for drivingthe mechanism to which power is to be transmitted through the gear. Forexample, a gear wheel 13 may be mounted on the shaft B. and the drivetaken from this wheel thus leaving clear the end of the shaft so as topermit of conveying through it .in the manner described hereunder'liquidunder pressure for controlling one or-more connecting devices.-

On the shaft A is fixed a sun wheel 0 which meshes with a series ofplanet wheels D conveniently three in number and disposed at equaldistances apart around the sun wheel 0. Around the planet wheels D andmeshing with them lies an internally toothed annulus E. The planetwheels D are carried by a disc member F which can rotate on the innerend of the driving shaft A this member F being rigidly connected to adisc F which in turn is coupled rigidly to the end of the driven shaft Bso that the latter shaft rotates as one with the parts F F as the planetwheels D move around the sun wheel G. The annulus E is carried byinwardly directed flanges or discs E E provided with suitable bearingsso that the annulus is free to rotate about the driving shaft A. Thedisc E carries on a cylindrical part or lateral flange E plates formingone member of a plate connecting device a the other plate members ofthis clutch being fixedin an annular chamber G suitably disposed withina casing H enclosing the whole" gear. This connecting device which, forconvenience, will be referred to as connecting device No. 1, enables thetoothed annulus E to be held against rotation when desired. Theconnecting device is adapted to be controlled by liquid pressure theliquid being delivered through a pipe 1 into an annular chamber G whereit can act on a series of plungers such as G? through vwhich pressurecan be applied to the plates of the conne ting device 1 so as to causeengagement between the parts of the connecting device. Coiled springscause the return movement of the plungers G when the liquid pressure isrelieved. The liquid pressure is so controllable that the pressure onthe connecting de- .nndreleased in a similar manner as required.

By thus/permitting slip between the members of the connecting device andbringin them into gradual engagement as the li ui pressure on theconnecting device mem rs is increased, shocks and undue strains on themechanism are avoided While, moreover, the slipping of the connectingdevice provides in effect an increased range of the speed ratiosobtainable with'the' gear.

The disc member E of the toothed annulus E carries at its peripheralpart the lates forming one member of a connecting evice 2 of which theother member is carried by the disc F. This connecting device 2 servesto couple together the toothed annulus E and the rotatable member F Fwhich carries the planet wheels D and is in turn coupled to the drivenshaft B. The connecting device 2 is constructed and controlled by liquidpressure in a manner similar to the clutch 1 so that the connectingdevice 2 can.

be applied or released gradually with a varying degree of slip. Theliquid for controlling the connecting device 2 is delivered through apipe 2 which passes down' the center of the driven shaft B andcommunicates with a radial passage F formed within the disc F whence apassage F leads to an annular chamber F wherein are a series of plungersadapted to act on the plates of the connecting device as in the case ofthe connecting device No. 1.

In this construction if both connecting devices 1 and 2 are released,the driving shaft A will rotate the sun wheel G without effect on thedriven shaft B. If'the connecting device 1 is engaged, thereby holdingthe toothed annulus E against rotation, the shaft B will be driven at areduced speed. By

engaged, a direct drive will be obtained, the

shaft B being rotated at the same speed as the driving shaft A.-Reduction of the gear ratio gradually so as to culminate in this directdrive is possible by the slipping and gradaul engagement of the membersof the connecting device 2. I

Thus by means of the above described mechanism, it is possible totransmit the drive from the shaft A to the. shaft by such aduations aswill have substantially the egct of an infinite range of gear ratiosleadin up to the fixed ratio of the wheels and thence to thedirectdrive.

Referring to the variable speed gear illustrated in Figure 2, thiscomprises in efi'ect a gear train similar to that shown in Fi re 1combined with a second and substantially similar gear train throughwhich the drive is transmitted from the driving shaft to the drivenshaft B. The parts COIIIFIlSllIg the first gear. train shown in thelet-hand portion of Figure 2 are constructed and arranged in substantiallythe same way as the gear train illustrated in Figure 1. There is a sunwheel 0 fixed on the driving shaft A and this sun wheel meshes with aseries of planet wheels'l) disposed around it. These planet wheels inturn mesh w1th an internally toothed annulus E which is mounted looselabout the shaft A. A plate connecting device 1 comprising membersrespectively carried on the casing H which encloses the whole gear andon a part such as a flange E on the disc E connected to the annulus Eserves to enable this annulus to be held against rotation. A plateconnecting device 2 whose members are respectively carried by theannulus E and by the rotatable member F F which in turn carries theplanet wheels D enables the toothed annulus tobe coupled to the planetwheel carrier. In this case, however, this planet wheel carrier F F isnot coupled directly to the end of the driven shaft B but is connectedto the internal] toothed annulus J of the second gear tram. The member FF also carries the plates forming one member of another plate connectingdevice 3. As shown, the connecting devices 2 and 3 are convenientlydisposed on either side of the disc F being arranged in annular chambersF".F, the toothed annulus J being mounted on the chamber F. second geartrain are mounted on a disc or the like K fixed on the inner end of thedriven shaft B and to this lanet-carrying member K is connected atiiinged disk K on the flange of which are mounted the plates formingthe second member of the connecting device 3. The planet wheelsK mesh onthe one hand with the toothed annulus J and on the other hand with a sunwheel L mounted loosely on the driven shaft B. The sun wheel L isdisposed on a sleeve 1 having a flanged disc member L- which carriesplates forming one member of a connecting device 4. The plates formingthe other member of this connecting device are fixed in a chamber Mmounted rigidly in the'casing H.

Connecting device 1 serves to hold against rotation the toothed annulusE of the first ber The planet wheels K of the gear train. Connectincouple the toothed ann us E to the rotatable member F F which carriesboth the planet wheels D of the first gear train and the toothed annulusJ of the second gear train. Connecting device 3 serves to couple therotatable member F F with the planet wheels D and the toothed annulus Jto the driven shaft B. Connecting device 4 serves to hold the sun wheelL against rotation. All these connecting devices are controlled byliquid pressure the li uid being delivered to connecting device 1 trough the pipe 1 which leads out through. the casing H. The liquid flowsto and from the connecting devices 2 and 3 through concentric pipes 2and 3" which run through a passage within the driven shaft B. At theirinner ends these pipes terminate in the centre of and rotate with thedisc F the pipe 2 leading to a r dial passage F whence the liquid canflow the axial direction through a passage F into the annular chamber Fwhere it can act on plungers operative on the plates of the connectingdevice 2 in the same way as described with reference to the operation ofconnecting device No. 1 in the construction shown in Figure 1. The pipe3 leads into a radial passage F which communicates in turn by a passageF extending in the axial direction with an annular chamber F"; Thepressure of the liquid in this chamber can act through a series ofplungers on the plates of the connecting device 3. The liquid underpressure is conveyed to the connecting device No. 4 through a pipe 4which leads throu h the casing H into an annular chamfixed in thiscasing where the liquid pressure can act through a series of plungers onthe connecting device plates.

If all the connecting devices are disengaged, the driving shaft A canrotate without transmitting any power to the shaft B. If it is desiredto bring the lowest gear ratio into operation, connecting devices 1 and4 are engaged, the engagement in the case of either one or both of theseconnecting devices being gradual, such variable slip being permitted asthe pressure increases as will device 2 serves to cause the fixed gearratio to be reached i smoothly and without undue shock or strain on themechanism. By the engagement of connecting devices 1 and 4, the toothedannulus E in the first gear train and the sun wheel L in the second cartrain are held against rotation. At this time the connecting devices 2and 3 are disengaged.

In order to pass to the .next gear ratio, connecting device 1 is stillmaintained engaged but connecting device 4 is released so as to free thesun wheel L and connecting device 3 is gradually engaged. In this way,while the toothed annulus E is still held against rotation, the member FF which carries the planet wheels D in the first gear train is coupledto the driven shaft B, the

- members of the second gear train then being 3 the toothed annulus E tothe rotatable memher F F and-holding the sun wheel L I against rotation.

If a direct drive is desired, connecting devices 2 and 3 are engagedwhile connecting devices 1' and 4 are released. The toothed annulus Ewill then be coupled to the member F F which carries the planet wheels Dthis member in turn being coupled to the driven shaft B. The gear wheelsin the two trains will then' be lockedtogether and to the driving anddriven shafts.

Turning now to the construction shown in Figure 3, this illustrates analternative arrangement for a single gear trainl -As in the case of thesingle gear train shown in Figure 1, that illustrated in Figure 3comprises a sun wheel C which, however, in this instance is carriedloosely on the driving shaft A, a series of planet wheels D which arepositively connected to the driven shaft 13-, and an internally toothedannulus E. In place of the single gear train being controlled by twoconnecting devices, as in the construction shown in Figure 1, the gearshown in Figure 8 is controlled by four connecting devices of the platetype each of which is actuated by liquid presure so that the connectingdevice members can be brought into or out of engagement with a variabledegree of slip between them. As mentioned, the sun wheel C is in'thiscase losely mounted but can be coupled'to the driving shaft A or,alternately, held against rotation. By this means it is possible toobtain two alternative fixed gear ratios in addition to a direct drive,whereas with the single gear train shown in Figure 1, only one fixedgear ratio and a direct drive is obtainable as is apparent from thedescription above. a

The details of the construction shown diagrammatically in Figure 3 areas follows:

The sun wheel C is mounted about the centre of the length of .a sleevemember C" C which can rotate freely on the driving shaft A.

. That part Cf of this sleeve which is directed towardsthe end of thedriving shaft A to which the power is applied carries the plates.

' forming one member of the connecting device 3*. The other plate memberof this connecting device is carried by a disc A fixed on the drivingshaft A. .The other part C of the sleeve which carries thesun wheel Csurrounds the inner end of the driving shaft A and carries the platesforming one member of the connecting device 4*.

The other plate member of this connecting device is mounted in anannular chamber on out through the hollow driven shaft is held againstrotation. The connecting device 3* thus enables the sun wheel to becoupled to the driving shaft A while the.

sun wheel;

connectin device 4* enables this to be hel against rotation.

The internally toothed anulus E is mounted about the centreofthe lengthof -a cylindrical member E E, the ends of which are provided withsuitably arranged disc-like bearing members rotatable respectivelyon thedriving shaft A andon the driven shaft' B. On the part E of thiscylindrical memher are mounted the plates forming one member of theconnecting device 2*, the

other member of this connecting device bein mounted on the disc A of thedrivin A. On the part E of the cylindric memshe.

her are mounted plates forming one member of the connecting device 1*the plates forming the other member of this connecting device beingdisposed in an annular chamber- 0 which is fixed within the casing Henclosing the whole gear. The connecting device 2* enables, the toothedannulus E to be coupled to the driving shaft A while the connectingdevice 1* enables this annulus to be held against rotation.

When it is desired to bring into operation the first fixed gear ratio,connecting devices a disc N fixed on a shaft N which sses and 1* and 3*are engaged whereby the sun wheel I G will be coulgled to the drivingshaft A and the annulus will be held a ainst rotation. This hastherefore substantially the same efl'ect as engaging the connectingdevice 1 in the gear mechanism shown in Figure 1.

When it is desired to bring the second fixed gear ratio into operation,connecting devices 1* and 3* are released and connecting devices 2* and4* are engaged. This results in the toothed annulus E being coupled tothe driving shaft A while the sun wheel G is held against rotation. Ineach of these cases, the drive is taken off through the planet wheels Dand the driven shaft B.

When it is desired to obtain a direct drive, connecting devices 2* and3* are engaged, thereby cougzlling both the sun wheel G and the annulusto the driving shaft A so that the whole gear rotates solid.

The several connectingdevices are controlled by liquid under ressure insuch a way that the plates can brought-gradually into engagement ordisengaged with a variable degree of slip so that'in effect an infiniterange of gear ratios can be obtained between the fixed ratios determinedby the one method of controlling I the connecting devices in thegear-construction shown in withm the =valve body Sagesinthe "th'ec apartfrom the port 10,

' the port ential direction trolled by a hollow 'with a chamber snwhence other means.

Figure 2 soastob theseconnecting deyiocs iutli operafion dirclease themin their proper sequence. The flow of liquidnnder pressure isconcylindl'icalvalve which isrotatable within a valve body or casing Q.Liquid under pressures delivered by a. pump B into an accumulator Rwhence it flows through a pipe R mto the end of the casing Q, the liquidthen having access to the interior-P valve P, as shown in Figure 4. Aport S in the casing Q communicates 'by' a pipes the liquidYis drawn bythe pump R. Thus the liquid supplied under pressure flows through thepipe Rinto the interior P of the valve P and "after to the severalclutches returns through the relief port S to the chamber S when theprmre on the clutches is Trelieved. ,The valve P can be rotated Q bymeansof a lever P 'adaptedto be fll'rugemen t'of the ports and passhviirlve Qdand the valve ownin iguresSm 9. along first Q, it will beseen. that the pipes 1", 2", 3 4" leading from the several connectingdevices 1, 2, 3 and-tare carried to the casing Qterminate in thecylindrical interior 0 mg in correspondin' g ports 10, 20, and 40, asshown in Figure 9. These ports; however, are arranged in the order 10,40, 30, w around of the casing Q; The port is spaced 30 while there is adistance between the The similar circumferential ports 30 and 40, butthere is double the dis- U tance, namely of are, between the'ports 30and 20. There'extends, however, from towards the port 30 for a dis}tanceof 30 of a groove 20", while a similar circumferential groove 10 oflike length, namely 30 of are, extends from the port 10 in the directionof the port 20. The

relief port S is positioned in the circumfer- 30 of are from theport-.20 but is not in line therewith, being placed further along the Q.On the other hand, the port 10 with its groove 10", the ports 10- and 30and V groove 20 are all in line, that is, in the same plane normal tothe valve axis, as shown-in r igure 9. From each of these ports thereextend in the longitudinal direction of -the casing Q passages whichterminate respectively in other ports. Thus from the port 10 there runsa by-pass passage 11 which terminates in a there runs a by-pass passage41 which terminatesin a port 42., 41 extends in the longitudinaldirection for a distance three times thelength of the by-pa'ss p 11.From the port 30 a of the hollow U and U the interion the port 20 withits port 12. From the port 40v The by-pass passage by-pass passage 31leads to a port 32, the W passage 31 being the by-pass passage 41,. 20"a by-passfipassage 21 having the same length as the passage 11 leads toa; port 22. The ports; 12 and 22 lie in one plane normal to'thevalveaxis, while the ports'32 and 42 lie in one plane normal-to the valveaxis. The relief port S lies in a similar plane which is situated midway:in the direction between the plane in which of the valve axis 7 and 42and thelplane in same length as the lie the ports 32 which lie the ports12 and 22.

Turning now to the formation of the exteriorof the-valve Pas shown in Fi8, ;i t will. be seen that thishasformed in it -two portsT and T whichpass through the valve body into its interior-P. These ports aresituated in the same plane normal to the valve axis'andthis plane isdisposed so as togcoincide with the plane in which lie theports 10, 20,30 and 40 formed in the valve casing Q. The exterior surface of thevalve Phas formed in it a'series of grooves which extend bothslongitudinally as indicated in Figure 8. The principal one of'thesegrooves U runs the wh0le way round th the relief port S in thelongitudinal. direction, and extending circumferentially-in planessituated on either sideof the groove U are two other grooves The grooveU runs for a dis tance of 210. of are around the valve while the groove-U runs for a distanceof 180 of are aroundthe valve. 'Atone end, thegroove U communicates with the groove by a groove U which runs in thelon itudinal direction at right angles to t e groove U, thegroove Uhowever, being carried beyond the grooveU so hat the end of the groove Uwill terminate in the same plane normal to the valve axis as that inwhich lies the groove U Another and The control of the severalconnect-ing de-' vices in the mechanism illustrated in Figure 2 isbrought about by operation of the above described valve mechanism in thefollowing way: In the position in which the valve is shown in Figure 5with the pressure deliver- 1ng ports T T closed, the pressure is relieved from all the connecting devices so that the gear will beinoperative and no power will be transmitted from the. driving shaft Ato the driven shaft B. Iffnow the valve P is rotated by means of thelever P so as circumferentially and Finally, from the port the valve ina plane L .adapted to coincide wi 1n the casing Q.- Spaced equally apartfrom,

shorter longitudinal groove U extends from to bring the ports T..T' intoregisterwith the end of the groove 10" commumcating with the port 10 andthe port 40, liquid under pressure from the interior P of the valve canflow through the pipes 1 1 and 4 t to the connecting devices 1 and 4:,thus brmging into operation the first gear. At this time the pipes 2 and3 W111 be open to relief since the ports 20 and 30 are in communlcationwith the groove U whence the pressure can be relieved by way of therelief port S. If the valve is now turned through 30 of arc the port Twill be brought into register with the port 30, the port 40 now beingclosed. The port T will, however, still allow llquid under pressure toflow into the p pe 1 by reason of the circumferential spacing apart ofthe ports T T and the provision of the oove 1O communicating with theport 10. ressure will now be applied through the pipe connections 3 3 tothe connecting device 3 which will be in operation together with theconnecting device 1, thus brigmg into use the second gear. At this timethe pressure will be relieved from the connecting devices '2 and 4.Further rotat1on of the valve P through 30 of are will bring the port Tinto register with the end of the groove 20 while the port T Wlllregister with the port 40. Pressure will now be admitted by the pipes 22* and d 4:? to the connecting devices 2 and 4:, thus br nging intooperation the third gear. At this time the ressure will be relieved fromthe connecting evices l and 3. Finally, if the valve is turned through afurther 30 of are so as to bring the port T opposite the port 20 and theport 1" into register with the port 3(), pressure will be applied to theconnecting devices 2 and 3 while the pressure will be relieved fromconnecting devices 1 and 4, the result being a direct drive.

The pipes 2 and 3 rotate with the disc member F to which one end of eachof these concentric pipes is connnected. The outer ends of these pi es 2and 3 extend beyond theouter end 0? the driven shaft B into a fixedmember V shown in Figure 5. The ends of the ipes can rotate in thisfixed member in w 3 res ectively. The liquid uner pressure supphedthrough these pipes 2 and 3 can pass from the annular chambers V and Vthrou h o enings in the walls of the tubes 2 an 3 mto these tubespassing thence to the passages F and F.

Apparatus of a type similarto that described above may be employed forcontrolling the suppl of liquid under pressure to and relieving t ispressure from the several connecting devices in \the gears illustratedin Figures 1 and 3 and this controllmg mechanism in the case of eitherof the gear constructions shown may be actuated gear and annulusstationary, and two mul- 1ch are formed annular chain-l bers V and V'whencelead the ipes 2 -and.

by various means. It will be appreciated that b suitable movements ofthe controlling va vc the pressures as applied to the several connectingdevices may be adjusted as riequired so as to permit various degrees ofs 1p.

The details of construction may be modified as found necessary inaccordance with the purpose for which the improved gear is emp oyed.

What I claim as my invention and desire to secure by Letters Patentis 1. In a variable speed gear, in combination, a driving member, adriven member, means for coupling said driving member to said drivenmember including an epicyclic gear train comprising a sun wheel looselymounted concentrically of the driving member, a rotatable arm carrying aplanetary pinion connected to the drlven shaft, a toothed annulusconcentric with the driving and driven members but mounted to rotateindependently of either, a disc secured to the driving shaft, aplurality of multiple plate connecting devices operative on the elementsof the gear train for changing the speed ratio between the driving anddriven members, there being two of said multiple plate connectingdevices adapted to hold the sun tiple connecting devices adapted toconnect the sun gear and annulus to said disc secured to the drivingshaft, and means for controlling said connecting devices.

2. In a variable speed gear, in combination, a driving member, a drivenmember, means for coupling said driving member to said driven memberincluding two epicyclic gear trains, each comprising a sun wheel, arotatable arm carrying a planetary pinion, and a toothed annulus, thesun wheel of the first gear train being secured to the driving member,the" rotatable arm of the first train being secured to the annulus ofthe second, and the rotatable arm of the second gear train being securedto the driven member, a plurality of multiple plate connecting dev cesoperative on t e annulus of the-first train and-on the sun wheel of thesecond train for changing the speed ratio of the gear, and means forcontrolling said connectmg devices, said meansbeing adapted to permitavariable degree of slip between theplates of the connecting devices.

3. In a variable speed gear, in combination, a. drivingmember, a drivenmember, means for coupling said driving member to said driven memberincluding two epicyclic train being secured to the driven member, amultiple plate connecting device adapted to hold the annulus of thefirst gear train stationary, a second multiple plate connecting deviceadapted to lock the elements of the first train together, a thirdconnecting device adapted to lock the elements of the second traintogether, a fourth connectin device adapted to hold the sun wheel 0 thesecond train stationary, and means for com 10 devices.

In testimony whereof I have signed my name to this specification.

ALAN ERNEST LEOFRIC CHORLTQN.

